DISEASES OP THE EESPIBATOEY ORGANS. 119 



the danger; hence double pneumonia is more fatal than pneumonia 

 of one lung. 



THE WINDPIPE. 



The windpipe, or trachea as it is technically called, is the flexible 

 tube that extends from the larynx, which it succeeds at the throat, 

 to above the base of the heart in the chest, where it terminates by 

 dividing into the right and left bronchi— 'the tubes going to the right 

 and left lung, respectively. The windpipe is composed of about fifty 

 incomplete rings of cartilage united by ligaments. A muscular layer 

 is situated on the superior surface of the rings. Internally the tube 

 is lined with a continuation of the mucous membrane that lines the 

 entire respiratory tract, which here has very little sensibility in 

 contrast to that lining the larynx, which is endowed with exquisite 

 sensitiveness. 



The windpipe is not subject to any special disease, but is more or 

 less affected during laryngitis (sore throat), influenza, bronchitis, 

 etc., and requires no special treatment. The membrane may be left 

 in a thickened condition after these attacks. One or more of the 

 rings may be accidentally fractured, or the tube may be distorted or 

 malformed as the result of violent injury. After the operation of 

 tracheotomy it is not uncommon to fimd a tumor or malformation as 

 a result, or sequel, of the operation. In passing over this section 

 attention is merely called to these defects, as they require no particu- 

 lar attention in the way of treatment. It may be stated, however, 

 that any one of the before-mentioned conditions may constitute one 

 of the causes of noisy respiration described as " thick wind." 



GUTTURAL POUCHES. 



These two sacs are situated above the throat, and communicate 

 with the pharynx, as well as with the cavity of the tympanum of 

 the ear. They are peculiar to solipeds. Normally, they contain air. 

 Their function is unknown. 



One or both guttural pouches may contain pus. The symptoms are 

 as follows: Swelling on the side below the ear and an intermittent 

 discharge of matter from one or both nostrils, especially when the 

 head is depressed. 



The swelling is soft, and, if pressed upon, matter will escape from 

 the nose if the head is depressed. As before mentioned, these 

 pouches communicate with the pharynx, and through this small 

 opening matter may escape. A recovery is probable if the animal is 

 turned out to graze, or if he is fed from the ground, as the dependent 

 position of the head favors the escape of matter from the pouches. 

 In addition to this, give the tonics recommended for nasal gleet. If 

 this treatment fails, an operation must be performed, which should 

 not be attempted by any one unacquainted with the anatomy of the 

 part. 



